Safety joint for use in well strings



2 Sheets-Sheet l July 3l, 1951 T. A. cRElGHToN SAFETY JOINT FOR USE 1NWELL STRINGS Filed Aug. 9, 1946 July 31, 1951 1', A; cRElGHToN l SAFETYJOINT FOR USE IN WELL STRINGS 2 'Sheet's-Sheet Filed Aug. 9, 1946 W'mw NN mi.

Patented July 31, 1951 Thomas s.. ereignen, Long Beach, Calif.; veraNeva Creighton executrix of said Thomas A.

Creighton, deceased Application August 9, 1946, Serial No. 689,623

use in a well string andit is a general object of the invention toprovide a joint construction and operator therefor whereby a well stringsuch as a string of drill pipe or the like can' be parted at a selectedpoint whenever desired,- or neces- Sary y v Releasable connections orsafety joints are desirable in well string and particularly in drillingstrings since there are times when it becomes necessary or desirable toseparate Vparts or" a. string while it is in the well. For example, inthe course of drilling with the rotary method the bit is operated bymeans of a string of drill pipe vknown ordinarily as the Adrillingstring, and it sometimes occurs that the bit or a portion of the drillstring becomes stuck so that it cannot be withdrawn from the well. If nomeans is provided for disconnecting or breaking'the string at one ormore predetermined points along-.its length it becomes necessary to tryto remove it by iishing operations or by cutting it out and by any suchmeans kor method the operation is hazardous, slow and expensive. Safetyjoints have been "proposed and in some Claims. (Cl. Z55-48) cases usedin well drilling strings.- However, they are generally unsatisfactorybecause they are not always dependable and in most instances in troduceeither a weak point in the drilling string or present hazards which areimpractical.

It is a general objectv "of this invention' to provide a jointconstruction and operator therefor whereby a well string such, forexample, as a string of drill pipe, can be disconnected or parted at anypredetermined point ina well without resorting to fishing operations,cutting operations, or other like hazardous or costly methods.

A further object of my present invention is to provide a constructionwhich enables the use of a plurality of joints or couplings in a singlestring under control of a simple, dependable operating device or toolwhereby any one of the joints in the string can at will be releasedwithout in-` terfering with other joints. l

Itis a further object of my present invention to provide a jointconstruction which involves few simple parts which are of sturdy,dependable construction and which are easily formed andina-- nip-ulated.The joint or coupling provided by the present invention. resembles anordinary tool joint in that it involves, primarily, a box section and apin section threaded together andV in addition to such parts it involvesa locking memn ber or locking liner splined to both sections andshiitable longitudinally out of engagement with 2 one of the sectionswhen it is desired to release lthe joint.

Itis another object of rnyinvention to provide a simple easilymanipulated, dependable tool iol' operating the joint of the presentinvention, which tool can be run into the well on a wire line and whichAis effective in engaging the joint in a proper manner and is operable toeffectively actuate the lock liner of the joint.

The various objects and features of my inven tionwill be fullyunderstood from the following detailed description of a typicalpreferred forro and application of the invention, throughout whichdescription reference is made to the ao companying drawings, in which:

Fig. 1 is a sectional view of a well showing a well string or string ofdrill pipe therein which well string is shown provided at spaced pointswith couplings embodying the present invention. Fig. 2 is a longitudinaldetailed sectional view of a coupling embodying the present inventionshowing it in locked or operating position and showing the operatingtool that I have provided in position ready to be operated to releasethe joint or coupling. Figs. 3, 4 and 5 are detailed transversesectional views taken on lines 3 3, ei-4, and 5 5, respectively, on Fig.2. Fig. 6 is a longitude nal detailed sectional View of a portion of thedrilling string taken through a coupling provided by the presentinvention showing the string clear or unobstructed as it is duringnormal operating conditions. Fig. lv is a view similar to Fig. 6except'that it shows the operator or operating tool of the presentinvention lowered` into the string to a position from which it isadapted to be moved upward preliminary to being engaged with the lockliner or" the joint, and Fig. 8 is a View similar to Fig. 7 showing theoperator after it has been engaged with the lock liner of the joint andthe lock Vliner has been operated or moved to a position where the jointis released ready to be disconnected.

The equipment that I have provided bymy invention involves two distinctparts or units one a joint structure proper and the other an operator oroperating tool that cooperates with the joint to release the joint sothat it can be disconnected. ln carrying out my invention I may provideasingle well string S` with any desired number of couplings C embodyingthe present invention and I may locate the couplings at any suitable ordesired points lengthwise of the string. In Fig. l of the drawing I haveshown a well provided with a typical casing lil and have shown a wellstring S within the casing and involving lengths or sections of pipesuch as drill pipe II joined by the usual joints I2 and having couplingsC of the present invention inserted in certain of the joints I2 at thedesired points.

The coupling C that I have provided may be applied directly to thesections of pipe to be connected although in practice it is advantageousto insert it in a joint I2 as I have shown in the; drawings. I show thecoupling construction inserted between the upper part I3 of a joint andthe lower part I4 thereof, the upper part being in the nature of a pinsection having a tapered downwardly projecting pin part I5 and the lowerpart I4 being in the nature of a box section having an upwardly facingthreaded box portion It to receive the pin.

The joint C of the present invention involves, primarily, three parts,two main sections l1 and I8 joined by threads I9 and a lock liner 2Bthat extends between and locks the sections l1 and I8 against beingunthreaded. Where the joint C is to be applied as I have shown in thedrawings the upper section I'l is provided at its upper end with a boxportion 2i adapted to receive the pin I5 while the lower section I8 isprovided at its lower end with a pin 22 adapted to be threaded into thebox I6. The pin I5 and box 2| are threaded together in the manner commonto tool joints, for instance, by coarse tapered threads and the pin 'Z2and box I6 are threaded together in like manner. In accordance withstandard practice it is preferred to make the threaded connections justdescribed righthanded or such that they make up or tighten as the stringS is operated or rotated in a righthanded direction, which is thedirection in which it is rotated during vnormal operation.

In accordance with my invention the threaded connection between thesections I1 and I8 of the coupling or safety joint is established byproviding a tapered pin 25 on one section to engage a socket portion 2Ein the other section. The pin and socket connection may be straight or,as I have shown throughout the drawings, it may be tapered. In theparticular case illustrated I have shown a pin 25 projecting from thelower end of the section Il' and I have shown a socket part 26 on theupper end of the section I8. I prefer to provide a tapered t between theparts 25 and 26 and to provide coarse threads 2l and 28 on the parts 25and Z6, respectively, which threads serve as the means joining orconnecting the sections I'I and I8. In the preferred construction thethreads 2l and 28 are pitched opposite to those of the parts hereinabovedescribed, or in other words, they are made lefthanded so that thecoupling C is disengaged upon rotation of the upper portion of thestring in a righthanded direction.

The lock liner 2S which I provide is an elongate tubular part fittedwithin the sections I1 and I8 having splined or keyed engagementtherewith. In accordance with my invention the bores 3l) and 3l of thesections Il and I8, respectively, are provided with longitudinal keywaysor splines 32 and 33, respectively, and the exterior of the lock liner20 is correspondingly keyed or splined to have parts that mesh with or tthe splines 32 and 33. This splined connection or engagement is clearlyillustrated in Figs. 4 and 5 of the drawings. In accordance with mypreferred construction the bore 30 or opening in the upper section Ilextends downwardly and continuously through the section I'I from thesocket 2l to the lower end of the pin 25 while the bore 32 in section I8extends downwardly in the section I8.

lower portion is within the section I8 and since it has splinedengagement with both sections it serves when in this position as a keyor lock positively preventing relative rotation between the sections l1and I8.

I may t the lock liner 20 into either one or both of the sections I? orI8 so that it is tight and requires positive operation to move it fromtheposition just described. However, I prefer to provide releasableretaining means that holds it in this position. In practice I mayprovide one or more detents or springs to hold the liner in activeposition. As shown throughout the drawings it is desirable to provide ashear pin 42 which acts to releasably hold the lock liner 20 in activeposition. I have shown a shear pin carried by the section I8 to extendinto an opening in the lock liner and, in practice, I form the shear pinof a material that has the desired shear strength.

In forming and relating the parts of the coupling or joint C with theusual parts found on a well string S Ysuch as the parts I3 and I4 Iprefer to make the bore 43 of the lock liner 20 substantially equal insize to the bores or openings 44 through the parts I3 and I4. In suchcase there is left or established an enlarged part or a portion ofenlarged diameter at X above the lock liner 2|] and a similar enlargedpart Y below the lock liner 2U.

The operator that I have provided, that is the tool that I provide foroperating the joint above described involves, generally, a body 45 whichis an elongate part small enough in diameter to t freely through thebores 43 and 44, or, in other words, of a size that can be freely runthrough the string and the various joints or couplings included therein.The body 45 is preferably run into the string S on or by means of a lineL, and I prefer to couple the body to the lower end of the line Lthrough or by means of a jar J and a sinker bar 45, the jar beingprovided as a means by which a jarring action can be imparted to thebody and the sinker bar being provided as a mass whereby an effectiveblow is gained through the jar. The operator that I have providedfurther includes one or more grabs or dogs 50 carried by the body andeffective to cooperate with the lock liner 20 and it includes means 5Ifor expanding the dogs 5B to working position upon the tool beingmanipulated in a predetermined manner.

The body 45 in its preferred form is a simple elongate part round incross section and provided with side recesses 56 in which the dogs 50are carried. In the particular arrangement illustrated I show three dogs50 it being understood that any desired number of dogs may be employedas circumstances may require.

Each dog 5U is retained in its recess 55 by or on a pivot pin 5'I and itis so formed and shaped as to normally hang by gravity in a retractedposition such as is shown in Fig. 7 of the drawings. In the retractedposition the dog 5@ will pass freely through the various openings orparts of the string S without interference. In its preand out as shownin Fig. 2 the finger extends v substantially straight down. Inconstructing the dog 5S I provide a working shoulder (iiiv at the outerend of the linger 59 which shoulder faces down when the linger is outand extends down as shown in Fig. 2. Further, I provide the finger witha smooth and preferably straight outer side or face @Iv which extendsdownwardly and inwardly from the point where the arm joins the nger whenthe dog is retracted as shown in Fig. 7, and I provide the dog with aninner sideV or faceSZ which is a straight cam face except near the outerend of the dog where it is beveled or pitched as at $3.

The means 5i for expanding or operating the dogs 5e preferably includesa stern 'I0 slidably supported by the body iii and depending therefrom,an operating head 'II on the upper end of the stem operating in achamber 'I2 formed in the body from its lower end and a tail piece-friction control forthe stem IQ. The stern enters the lower end of thebody or extends into the chamber 'F2 through a retainer Mi threaded intothe lower end of the body while the head'fII is an enlargement on thestem and is held by the retainer so the stem does not drop out of theVbody. The lhead Il has a rounded upper end which when the head is movedupward from a` down position, as shown in Fig. 7, engages the endportions S3 of the cam faces of the dogs and then rides up along the camfaces E2 causing bowed outwardly and are such as to normally'Yfrictionally engage in thewell string or in the bore M of a part on thewell string to establish resistance or to create friction. A springpressed latch 85 is carried in a recess 85 in the lower end portion ofthe stem IIJ and isl such that the lower collar 32 can be moveddownwardly past it but is checked against upward movement on the stemaiter it has passed down and over the latch.

In operating the equipment that I have provided the drilling string S isequipped with one yor more safety joints or couplings C such as I haveabove described and when these joints are made up tight the lock linears20 are arranged in place and the shear'pins 42 are applied to retainthem in operating position as shown in Fig. 6. When it is desired torelease one of the joints or couplings C the operator or operating toolthat I have described is lowered into the string on the line L and as itis lowered into the string the upper collar BI of the friction meansbears against the retainer i@ or the lowerrendof the body 135 so thatthe friction-device is pushed down through the string S or through thebores d4 that are of somewhat reduced diameter and which may occur atvarious points in the string. When the operator is thus lowered into thestring the stem 'Ill is suspended from the head 1I supported by theretainer 'I4 so that theheadis out of engagement with the dogs 5l] whichdogs will hang by gravity in a retracted position.

The operator having inserted the couplings C at predetermined pointsknows their location and runs the operating tool down somewhat below thejoint C which is to be released. He then pulls the line up moving theoperating tool up .into or beyond the coupler to. be released. When thefriction device on the stem Ill moves into the bore 44 of a part I4 orthe like it stops its upward movement while the rest of the tool ismoved upward with. the result that the stern 'Ill moves up through thefriction device until the latch 85 is engaged over the lower collar 82.This upward movement of the tool can be oontinued until the dogs 593 aresomewhat above the coupler to be reduced and when suflicient movementhas taken place to assure engagement of the latch over collar 82 thetool is then lowered and as it is lowered the head 'II on the stern. 16moves up between or inside the dogs 5B and tends to spread themoutwardly. If the dogs are in a part such as bore M of part I3 theycannot be spread to a full out position' but tend to move out and as thetool is lowered the dogs bear out until they come opposite theenlargement or cavity X above the lock liner Zit at which point they aremoved out to the fully expanded or operating position shown in Fig. 2.Continued downward movement of the tool causes the working shoulders 68of the dogs to engage the upper end of the lock liner 2li thusestablishing operative engagement between the tool and the liner 2B asshown in Fig. 2 oi the drawings.

The liner L is then manipulated so that the jar J acts to jar .the tooldownwardly and this action is made effective through the sinker bar Q6above the jar. The downward jarring action on the lock liner shears thepin d2 and is continued until the lock liner is forced or driven downout of section II and into section I8 at which time the threadedconnection between the sections I'I and I8 is freed to be released. Whenthis has been accomplished the operatingrtool can be withdrawn and torelease the threaded con'- nection between sections I'I andi@ the stringS is operated or rotated in the desired direction,v

for instance, wherefthe threaded connection to be released is lefthandedthe string is rotated in a righthanded direction which causes the jointto releaseor become entirely free.

A feature of the construction that I have provided is that I can provideas many safety joints or safety couplings as I desire in a single stringS and I can unlock or release these joints at will by simply loweringthe operating tool through the string to the desired joint and thenmanipulating it in the manner that I have described.

I have described the lock liner as being jarred downwardly. It will beapparent that I may reverse the arrangement so the liner is released byan upward jar,such reversal being within the alternative arrangementsthat are contemplated by the invention.

Having described only a typical preferred form and application of myinvention, I do not wish tobe limited or restricted to the specificdetails herein set forth, but Wish to reserve to myself any variationsor modications that may appear to those skilled in the art and fallwithin the scope of the following claims.

Having described my invention, I claim:

l. An elongate operator for a safety joint located ina well string andhaving releasably connected sections and a tubular lock part slidablyengaged with the sections and located centrally in the joint, the lockpart normally engaging both sections, having an upwardly facing portion,and being slidable to a position clear of one section, including, abody, means by which the body is lowered through the string and into thejoint, a dog carried by the body and normally in a retracted position,and means operating the dog to an operating position projecting from thebody to bear downwardly against the said upwardly facing portion of saidlock part, said means including an operating head loosely coupled to thebody for limited relative movement between the head and the bodylongitudinally of the operator, the body being movable downwardly froman elevated position'relative to the head whereby the dog engages thehead and is moved thereby to the said operating position, and a holdingmeans for the head including an element shiftable relative to the headin a direction longitudinally of the operator, a latch coupling the saidelement and head against relative movement upon the head being moved toa position elevated relative to said element, and a member on saidelement frictionally engaging the interior of the joint.

2. An elongate operator for a safety joint in a well string which jointhas an opening therethrough and has a shiftable lock part with anupwardly facing upper end, the operator including, a body insertableinto the opening of the joint, a dog pivotally carried by the body andnormally in a retracted position, and means to operate the dog intoengagement with said.V upper end of said lock part including, anoperating head, a stem carrying the head and connecting the head withthe body for relative movement between the body and head lengthwise ofthe operator, the dog being engageable with the head for operationthereby to a position where it projects from the body and opposes saidupper end of the lock part, and a holding means for the stem including,a drag frictionally engaging the well string and movable relative to thestem longitudinally of the operator and engaged by the body to be pushedthereby to operating position in the well string, and a latch carried bythe stein coupling the said drag and stem against relative movement uponthe stem being moved to an elevated position relative to the drag.

3. An elongate operator for a safety joint in a well string which jointhas an opening therethrough and has a shiftable central tubular lockpart with an exposed upper end, the operator including, a bodyinsertable into the opening of the joint from the upper end thereof, adog pivotally carried by the body-and normally in a retracted position,and means operating the dog into an operating position projecting fromthe body and engageable with said upper end of said part including, anoperating head, a stem carrying the head and connecting the head withthe body for relative movement between the head and body longitudinallyof the operator, the dog being engageable with the head to be operatedthereby to the operating position, and a holding means for the stemincluding a friction drag slidably carried by the stem below the bodyand frictionally engageable with the string to yieldingly resistmovement therein and engaged by the body to be pushed thereby tooperating position in the well string, and a latch carried by the stemto couple the said drag and stem 8 elevated to a predetermined positionrelative to the drag.

4. An elongate operator for a safety joint in a well string which jointhas an opening therethrough and has a shiftable tubular lock part withan exposed upper end, the operator including, a body insertable into theopening of the joint from its upper end, loosely linked elements coupledto the body for movement relative to each other longitudinally of theoperator, a dog pivotally carried by the body and normally in aretracted position, and means operating the dog to an operating positionengageable with said end of said part to depress said part, said meansincluding an operating head loosely linked to the body, the dog beingengageable with the head and operated thereby to the operating positionupon the body being lowered relative to the head, and a friction dragshiftable relative to the head longitudinally of the operator andengaging the string and yieldingly resisting movement of the head in thestring, the drag including a latch connecting the head and drag againstrelative movement upon the head being elevated to a predeterminedposition relative to the dog.

5. An elongate operator for a safety joint in a well string, which jointhas a central opening therethrough and has a central tubularlongitudinally shiftable lock part having an upwardly facing shoulder,the operator including, a body insertable into the opening of the jointfrom the upper end thereof, a jar above the body including looselylinked elements, a sinker bar above the jar and joined to one of saidelements, a dog pivotally carried by the body to normally hang in aretracted position, and means to operate the dog to an operatingposition engageable with the shoulder of said part including, anoperating head coupled with the body for relative movement between thehead and body longitudinally of the operator, the body being movablerelative to the head to a down position where the dog is engaged by thehead and moved thereby to the operating position, and a friction dragconnected with the head for relative movement between the f drag andhead longitudinally of the operator, the

drag having a member frictionally engaging the well string and having alatch connecting the drag and head against relative movement upon thehead being moved to a predetermined elevated position relative to thedrag.

6. In combination, a safety joint for a well string including twotubular sections for application to adjoining parts of the string,threads joining the sections, and a lock liner engaged within bothsections with keyed engagement therewith and shiftable lengthwise of thesections to a position removed from one section, and an elongateoperating tool including a body, a dog pivotally carried by the body tonormally hang in a retracted position, and means operating the dogoutwardly from the body to an operating position to engage downwardly onand to operate the liner including, an operating head coupled with thebody to shift relative thereto longitudinally of the operating tool, thebody being movable relative to the head to a down position where the dogis engaged by the head and moved thereby to the operating position, anda friction drag connected with the head for relative movement betweenthe drag and head longitudinally of the operator, the drag having amember frictionally engaging the well string and having a latchconnecting the drag and head against relaagainst relative movement uponthe stembeing l5 tive movement upon the head being moved to apredetermined elevated position relative to the drag.

7. In combination, a safety joint for a tubular well string including,two tubular sections for application to adjoining parts of the string,the sections having aligned openings therethrough for passing toolsoperated through the string, threads joining the sections, a tubularlock liner engaged within the sections and slidably keyed thereto to beshiftable lengthwise of the sections between a position where it isengaged with both sections and a position removed from one section, andmeans releasably retaining the liner in position where it engages bothsections, and an elongate operating tool including, a body operablethrough the string and joint, a dog pivotally carried by the body andoperable to an operating position where it engages downwardly on theliner, an operating head shiftable relative to the body longitudinallyof the tool and engaged by the dog and moving the dog to the operatingposition upon the body being lowered relative to the head, the stem andbody being shiftable relative to each other longitudinally of the tool,and a holding means governing movement of the stem relative to the bodyincluding, a friction device shiftable relative to the stemlongitudinally of the tool and frictionally engaging the string andresisting movement of the device longitudinally of the tool andfrictionally engaging the string and resisting movement of the devicelongitudinally in the string, the friction device being engaged by thebody to be pushed down thereby to operating position in the string, anda latch carried by the stem coupling the said device and stem againstrelative movement upon the stem being elevated to a predeterminedposition relative to said device.

8. In combination, a safety joint for a tubular well string including,two tubular sections for application to adjoining parts of the string,the sections having aligned openings therethrough for passing toolsoperated through the string, threads joining the sections, a tubularlock liner engaged Within the sections and slidably keyed thereto beshiftable lengthwise of the sections between a position where it isengaged with both sections and a position removed from one section, andmeans releasably retaining the liner in position where it engages bothsections, and an elongate operate tool including, a body operablethrough the string and joint, a jar coupled with the body and havingrelatively movable cooperating jar elements, a dog pivotally carried byvthe body operable to an operating position where it engages downwardlyon the liner, an operating head shiftable relative to the bodylongitudinally of the tool and engaged by the dog and moving the dog tothe operating position upon the body being lowered relative to the head,a stem carrying the head and coupled tothe body to shift relativethereto longitudinally of the tool, and a means governing movement ofthe stem relative to the body including, a friction device having anelement frictionally engaging the string and resisting movement of thedevice in the string, the friction device being engaged by the body -tobe pushed down thereby to operating position in the string, and a latchcarried by the stem coupling the said device and stem against relativemovement upon the stern being elevated to a predetermined positionrelative to said device.

9. In combination, a safety joint for a tubular well string including,two tubular sections for application to adjoining parts of the string,the sections having aligned openings therethrough for passing toolsoperated through the string, threads joining the sections, a tubularlock liner engaged within both sectionsand keyed thereto to be shiftablelengthwise of the sections to a position removed from one sectionI andmeans releasably retaining the liner in position where it engages bothsections, and an elongate operating tool including, a body operablethrough the string and joint, a jar coupled with the body and havingrelatively movable cooperating jar elements, a sinker bar above the jarand coupled to one of said jar elements, a dog pivotally carried vby the-body operable to an operating position where it engages downwardly onthe liner, an operating head coupled with the body for relative movementbetween the body and head longitudinally of the tool and adapted to beengaged by the dog and to move the dog to operating position upon thebody being moved down relative to the head, a stem carrying the head andslidably carried by the body, and a means governing movement of the stemrelative to the body including, a friction device movable relative tothe stem longitudinally of the tool and having a drag elementfrictionally engaging the string and resisting movement relative to thestring, the said means being engaged by the body to be pus-hed downthereby to operating position in the string, and a latch carried by thestem coupling the said device and stem against relative movement uponthe stem being elevated to a predetermined position relative to saiddevice.

10. An elongate operator for a safety joint located in a well string andhaving a shiftable tubular lock part located centrally in the jointincluding, a body, means by which the body is lowered through the stringand into the joint, a dog carried by the body to shift between aretracted position and an operating position where it engages downwardlyon and operates the lock part, and means operating the dog to theprojecting position including, an operating head coupled to the body toshift relative thereto longitudinally of the operator and engaged by thedog to move it to the operating position upon the body being moved to adown position relative to the head, a friction member engaging theinterior of the joint to resist movement longitudinally therein andcarried by the head for movement relative thereto longitudinally of theoperator, and a latch connecting the head and said member against saidrelative movement upon the head being moved to a predetermined upposition relative to the said member, the dog being pivotally mountedand normally held by gravity in the retracted position.

THOMAS A. CREIGHTON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,778,830 Irvine Oct. 21, 19301,801,334 Dallorf et a1 Apr. 21, 1931 1,883,071 Stone l Oct. 18, 19322,108,971 Olsen et al Feb. 22, 1938 2,153,812V Newton Apr. 11, 19392,210,815 Linney Aug. 6, 1940 2,302,856 Hamon NOV. 24, 1942

